runtime-v2: logYaml step

[brig]

new input param for log task: format: "yaml" to print log message as yaml: and alias for this: logYaml

- logYaml: {k: v}
- logYaml: ${anyExpression}
- task: log
  in:
     format: "yaml"
     msg: "myMessage"

instead of

- log: ${resource.prettyPrintYaml(myMessage)}